The cocktail party effect refers to the brain's ability to focus one's auditory attention on a particular stimulus while filtering out a range of other stimuli. In this scenario, Mrs. Salim's focused attention on the radio news causes her to ignore the auditory input from her husband, demonstrating selective auditory processing.

Illusions are misinterpretations of sensory information that is actually present in the environment. Unlike hallucinations, which occur in the absence of external stimuli, illusions involve a distortion of existing stimuli. They demonstrate how the brain actively constructs our perception, sometimes leading to errors when sensory input is ambiguous or conflicting.

Perceptual constancy is a fundamental cognitive process that allows the brain to perceive objects as having stable properties, such as size, shape, and color, even when the sensory input reaching the retina changes due to distance, angle, or lighting conditions. This mechanism ensures that our internal representation of the world remains consistent and reliable despite the dynamic nature of visual stimuli.

The scenario describes a classic experiment on inattentional blindness, where observers fail to perceive an unexpected stimulus because their attention is focused on a different task. Although the provided answer key lists 'Perceptual constancy', this is factually incorrect as the phenomenon is clearly inattentional blindness. Perceptual constancy refers to the ability to perceive objects as unchanging despite changes in sensory input, which is unrelated to the failure to notice an unexpected stimulus.

The question refers to the Gate-Control Theory of pain. Much like how opponent-process theory explains color perception through antagonistic neural pairs, the gate-control theory posits that a neural 'gate' in the spinal cord can open or close to allow or block pain signals from reaching the brain, effectively modulating the subjective experience of pain.

Stroboscopic movement is an illusion of motion that occurs when a series of static images are presented in rapid succession. Because the brain cannot process the individual images fast enough, it fills in the gaps, perceiving the sequence as smooth, continuous motion. This principle is the foundation of cinema and television, enabling the creation of dynamic visual experiences from a series of still frames.

The text suggests that human perception is not a perfect recording of reality but rather a constructive process. When individuals recall events, especially under stress, their brains often fill in gaps or interpret information based on existing schemas, leading to a reconstruction of the event. This explains why eyewitness testimony can be unreliable, as the memory is influenced by cognitive biases and the active process of interpreting sensory data during the original experience.

The Muller-Lyer illusion involves two lines of equal length that appear different due to the orientation of arrowheads at their ends. In architectural perception, this effect explains why corners of buildings, which resemble these arrowheads, create distortions in perceived length, causing some edges to appear longer or shorter than they actually are based on their orientation.

Perceptual constancy refers to the tendency to perceive objects as unchanging in size, shape, and color despite changes in the sensory input reaching the eyes. Dimension is a property of an object's physical space, not a category of perceptual constancy.

Texture gradient is a monocular depth cue where the density and detail of a surface appear to change as distance increases. Nearby surfaces show distinct, coarse details, while distant surfaces appear smoother and more uniform. This gradient provides the brain with information about the distance and orientation of surfaces in the visual field, helping us perceive depth and spatial layout effectively.